Effects Of Contrast Media Research Articles

Unsuspected pregnancy during hysterosalpingography.

Dear Editor Hysterosalpingography (HSG) is now increasingly used as the first-line investigation to assess the uterine cavity and tubal patency in infertility work-up. Most patients with a history of infertility do not use a contraceptive method and due to irregular menstrual cycles, menstrual history is not always reliable. In this letter, we emphasize on clinical implications for preventing inadvertently performed HSG during pregnancy. A 34-year-old woman with a four-year history of infertility was referred for routine base investigation by pelvic ultrasound before intrauterine insemination (IUI). HSG was carried out one month ago, 3 days after menstrual bleeding had stopped. Although she had regular menstruations, she had an abnormal bleeding one month ago and was unaware of her pregnancy and decidual bleeding was presumed as menstrual bleeding. Therefore, the patient was regarded as not pregnant and no β-HCG test was performed before the HSG procedure. HSG of this patient illustrated a large endometrial cavity with a filling defect, which was reported as myoma, and the patient was referred for ultrasound investigation of the uterine filling defect (Figure 1 A, ​,B).B). Ultrasonography showed a 6 to 6.5-week gestational age embryo without a heart rate. Abortion occurred after a few days. Although there have been only a few case reports on undiagnosed pregnancy during (HSG) (1-7), it is important to emphasize on the unusual radiological features of this condition to alert radiologists and gynecologists reporting HSG. Early pregnancy during HSG may be recognized by a double outlined uterine cavity (DOUC) and the intrauterine filling defect denotes the fetal sac (1-7).However, a normal HSG cannot exclude early pregnancy during HSG (1). Contrast media infiltrating the decidual lining is responsible for the DOUC appearance (Figure 2). This sign can also suggest hyperplasia or late normal secretory endometrium. The filling defect can also be a sign of endometrial polyp, submucosal myomas or synechiae. Detection of DOUC sign should assist the operator to terminate the introduction of contrast medium and make a certain interpretation of early pregnancy (2). Although there have been several reports on the normal outcome in such cases (1-7), the potential concerns are teratogenic risks, miscarriage and displacement of the fertilized ovum (ectopic pregnancy,) due to the side-effect of the flushing effect of contrast media (3). The risk of mutation is low due to low exposure during HSG and termination is not recommended (4). Figure 1. A and B, HSG illustrates a large endometrial cavity with a filling defect Figure 2. Double outlined uterine cavity (DOUC) due to contrast material infiltrating into the endometrium during early pregnancy (arrows). Inadvertently performed HSG during pregnancy can be prevented by: Pelvic ultrasound evaluation before HSG (3) Scheduling the procedure during the early proliferative phase Maintaining a high index of suspicion, and not relying solely on the menstrual history. A pregnancy test on the day of the procedure,even in women with regular cycles and particularly for women with one irregular cycle or amenorrhea is mandatory.

Renal function 'OK'? – an audit of appropriate vetting for contrast enhanced CTs

Background: Contrast Induced Nephropathy (CIN) is an acute deterioration without other adequate explanation and is an adverse effect of contrast media (CM) administration, leading to increased mortality and morbidity.

SU‐E‐T‐412: Effect of Ingested Contrast Media On Dose Reporting for GI Malignancies Comparing Multiple Dose Calculation Algorithms

Purpose:Varian AcurosXB calculates dose‐to‐medium (Dm) as well as the clinically prevalent dose‐to‐water (Dw). For abdominal malignancies, ingested contrast is used during simulation to delineate the treatment volume (TV) or outline the organ at risk (OAR), but this effect is transient. The purpose of this study is to evaluate the effect of contrast media on dose reporting using AAA, Acuros(Dw) and Acuros(Dm).Methods:Ingested contrast was contoured and either “forced” to water density or left uncorrected. Six plans were generated for 26 patients in Eclipse using identical leaf motions and MU values. The Acuros(Dm) forced density plan was our gold standard.Results:For 6MV plans where contrast was in the TV, AAA underrepresented the dose to the contrast region by 3.91%±3.08% (p=0.037) and 2.51%±1.25% (p=0.005) for unforced and forced densities respectively. Acuros(Dw) plans with unforced and forced densities overrepresented the dose by 2.97%±1.23% (p=.001) and 1.66%±0.24% (p=2.5e‐4). For 6MV plans where contrast was an OAR, all plans were not statistically significantly different from the Acuros(dm) plan. For 15MV plans where contrast was in the TV, AAA overrepresented the dose to the contrast region by 0.73%±0.49% (p=0.015) and 0.95%±0.39% (p=0.002) for unforced and forced densities respectively. Acuros(Dw) plans with unforced and forced densities overrepresented the dose by 2.15%±1.20% (p=0.009) and 1.00%±0.63% (p=0.007). Plans calculated with an unforced density in Acuros dm consistently showed the closest agreement to the Acuros(Dm) plan calculated with forced densities. For all 26 plans, the difference was ‐0.25%±0.84%.Conclusion:The appearance of contrast media will impact dose calculation. More clinical studies are needed to determine if dw and dm reporting shows any clinical significance. Care should be taken to force the density of contrast media in the GI region to a suitable value. As a fail safe condition, the use of Acuros(Dm) is recommended for these treatments.

The protective effect of single dose tadalafil in contrast-induced nephropathy: an experimental study.

Objective:Contrast-induced nephropathy (CIN) is one of the most common causes of acute renal failure in hospitalized patients. The direct toxic effect of contrast media; ischemic damage caused by reactive oxygen species; increased perivascular hydrostatic pressure; high viscosity and changes in the activity of vasoactive substances play important roles in the pathogenesis. Tadalafil inhibits the phosphodiesterase enzyme which destroys nitric oxide. Nitric oxide causes renal vasodilatation, increases renal medullar blood flow and mediates the removal of free oxygen radicals. Drugs that increase levels of nitric oxide are expected to reduce the development of contrast nephropathy due to contrast media. We aimed to test the hypothesis that tadalafil reduces the development of contrast nephropathy due to contrast toxicity.Methods:A total of 24 female Wistar albino rats, three groups of eight, were included in the study. After 48 hours of dehydration, contrast media (meglumine diatrozoate, 6 mL/kg) was administered to the first group, and contrast media with tadalafil (10 mg/kg) was administered to the second group. The third group served as the control group. Blood and tissue samples were taken 48 hours after this procedure.Results:Serum cystatin C, serum creatinine and blood urea nitrogen (BUN) values were significantly lower in the contrast with tadalafil group compared to the group given only contrast. Serum and tissue malondialdehyde (MDA) levels were significantly lower in the contrast with tadalafil group than in the contrast only group.Conclusion:These results demonstrate the protective effect of tadalafil in the prevention of CIN in rats.

Contrast-induced nephropathy; A literature review.

Contrast-induced nephropathy (CIN) is a common cause of acute kidney dysfunction. Directory of Open Access Journals, Google Scholar, PubMed, EBSCO and Web of Science have been searched. It is necessary to identify at risk patients at early stages to implement preventive strategies to decrease the incidence of this nephropathy. However, mechanisms of CIN have not fully explained yet. It seems that mechanisms which mediated by nitric oxide and prostaglandin-induced vasodilatation have been played a crucial role in the CIN. Hemodynamic changes of renal blood flow, which causes hypoxia in the renal medulla and direct toxic effects of contrast media on renal cells, are thought to contribute to the pathogenesis of CIN. Contrast media is normally divided into iso-osmolar, low-osmolar, and high-osmolar. N-acetylcysteine is considered as one of the best choices to prevent CIN in high-risk groups. The first aim to prevent CIN is identifying high-risk subjects and controlling associate risk factors. As significant differences existed between contrasts agents due to their physicochemical properties, low-osmolar or iso-osmolar contrast media should be used to prevent CIN in at-risk patients. The volume of contrast media should be as low as possible.

Hemodynamic and tubular changes induced by contrast media.

The incidence of acute kidney injury induced by contrast media (CI-AKI) is the third cause of AKI in hospitalized patients. Contrast media cause relevant alterations both in renal hemodynamics and in renal tubular cell function that lead to CI-AKI. The vasoconstriction of intrarenal vasculature is the main hemodynamic change induced by contrast media; the vasoconstriction is accompanied by a cascade of events leading to ischemia and reduction of glomerular filtration rate. Cytotoxicity of contrast media causes apoptosis of tubular cells with consequent formation of casts and worsening of ischemia. There is an interplay between the negative effects of contrast media on renal hemodynamics and on tubular cell function that leads to activation of renin-angiotensin system and increased production of reactive oxygen species (ROS) within the kidney. Production of ROS intensifies cellular hypoxia through endothelial dysfunction and alteration of mechanisms regulating tubular cells transport. The physiochemical characteristics of contrast media play a critical role in the incidence of CI-AKI. Guidelines suggest the use of either isoosmolar or low-osmolar contrast media rather than high-osmolar contrast media particularly in patients at increased risk of CI-AKI. Older age, presence of atherosclerosis, congestive heart failure, chronic renal disease, nephrotoxic drugs, and diuretics may multiply the risk of CI-AKI.

Study on application of ultrasound microbubbles in the diagnosis of buccal carcinoma and metastatic cervical lymph nodes in mice.

This project's aim was to explore the enhancing effect of contrast media on primary cancer and cervical metastatic lymph nodes of cheek carcinoma by local injection. Lymphatic metastasis cheek carcinoma mice models were established, then self-made contrast media was administered into the primary cheek carcinoma and harmonic mode imaging was performed to observe the enhancement of primary lesions and cervical metastatic lymph nodes. The echo intensity (EI) was compared. The detection rate of metastatic lymph nodes and inflammatory lymph nodes was 61% (17/28) and 50% (6/12) before contrast-enhanced ultrasound (CEUS) imaging and 82% (23/28) and 75% (9/12) after CEUS imaging. After CEUS imaging, the EI of primary cancer and cervical metastatic lymph nodes was significantly increased, (P<0.01). After injection of self-made contrast media via the primary lesion, it can enter the lymph duct and obviously enhance the effect of ultrasonography on cervical metastatic lymph nodes of cheek carcinoma.

Heme oxygenase-1 counteracts contrast media-induced endothelial cell dysfunction

Endothelial cell (EC) dysfunction is involved in the pathogenesis of contrast-induced acute kidney injury, which is a major adverse event following coronary angiography. In this study, we evaluated the effect of contrast media (CM) on human EC proliferation, migration, and inflammation, and determined if heme oxygenase-1 (HO-1) influences the biological actions of CM. We found that three distinct CM, including high-osmolar (diatrizoate), low-osmolar (iopamidol), and iso-osmolar (iodixanol), stimulated the expression of HO-1 protein and mRNA. The induction of HO-1 was associated with an increase in NF-E2-related factor-2 (Nrf2) activity and reactive oxygen species (ROS). CM also stimulated HO-1 promoter activity and this was prevented by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. In addition, the CM-mediated induction of HO-1 and activation of Nrf2 was abolished by acetylcysteine. Finally, CM inhibited the proliferation and migration of ECs and stimulated the expression of intercellular adhesion molecule-1 and the adhesion of monocytes on ECs. Inhibition or silencing of HO-1 exacerbated the anti-proliferative and inflammatory actions of CM but had no effect on the anti-migratory effect. Thus, induction of HO-1 via the ROS-Nrf2 pathway counteracts the anti-proliferative and inflammatory actions of CM. Therapeutic approaches targeting HO-1 may provide a novel approach in preventing CM-induced endothelial and organ dysfunction.

Association of central pulse pressure with contrast-induced nephropathy and clinical outcomes in patients undergoing coronary intervention

The increase in pulse pressure (PP) may be transmitted to the glomerulus and thus impair renal blood flow autoregulation. This subtle change could predispose patients to the detrimental effect of contrast media. We sought to determine whether elevated central PP is associated with increased contrast-induced nephropathy (CIN) and future cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). In total, 448 consecutive patients receiving PCI were enrolled. In each patient, central and peripheral blood pressures were measured before PCI. The occurrence of CIN was identified and defined as a rise in serum creatinine of 0.5 mg/dl or a 25% increase from the baseline value within 48 h after the procedure. All patients were then followed up for at least 3 years or until the occurrence of a major adverse cardiovascular event (MACE) including death, nonfatal myocardial infarction, and ischemic stroke after coronary intervention. Overall, CIN occurred in 52 (11.6%) patients. Patients developing CIN had higher baseline central PP (P = 0.004). Patients were then stratified into three groups (low/intermediate/high) according to baseline central PP. Compared to that with the lowest tertile of central PP, patients with the highest tertile of central PP had a significantly increased incidence of CIN after PCI (odds ratio, 2.94; 95% confidence interval, CI 1.02-8.51). By Cox regression analysis, elevated central PP was an independent predictor of future MACE in all patients undergoing PCI (hazard ratio, 2.07; 95% CI 1.04-4.12). Elevated baseline central PP was associated with an increased risk of CIN and future cardiovascular events in patients with PCI. Further clinical study may be indicated to determine whether pharmacological modulation on baseline central PP could prevent CIN and future MACE after PCI.

Comparison of Intravascular Ultrasound with Conventional Venography for Detection of Extracranial Venous Abnormalities Indicative of Chronic Cerebrospinal Venous Insufficiency

PurposeTo investigate prevalence of extracranial abnormalities in azygos and internal jugular (IJ) veins using conventional venography and intravascular ultrasound (IVUS) in patients with multiple sclerosis (MS) being evaluated for chronic cerebrospinal venous insufficiency, a condition of vascular hemodynamic dysfunction. Materials and MethodsPREMiSe (Prospective Randomized Endovascular therapy in Multiple Sclerosis) is a venous angioplasty study that enrolled 30 patients with relapsing MS. The patients fulfilled two or more venous hemodynamic extracranial Doppler sonography screening criteria. Phase I of the study included 10 patients and was planned to assess safety and standardize venography, IVUS, and angioplasty and blinding procedures; phase II enrolled 20 patients and further validated diagnostic assessments using the two invasive techniques. Venography was considered abnormal when ≥ 50% lumen-diameter restriction was detected. IVUS was considered abnormal when ≥ 50% lumen-diameter restriction, intraluminal defects, or reduced pulsatility was detected. ResultsNo venography-related or IVUS-related complications, including vessel rupture, thrombosis, or side effects of contrast media were recorded among the 30 study patients. IVUS-detected venous abnormalities, including chronic, organized, thrombus-like inclusions were observed in 85% of azygos, 50% of right IJ, and 83.3% of left IJ veins, whereas venography demonstrated stenosis of ≥ 50% in 50% of azygos, 55% of right IJ, and 72% of left IJ veins. Sensitivity of venography for detecting IVUS abnormalities was 52.9%, 73.3%, and 80% for the azygos, left IJ, and right IJ veins, respectively. ConclusionsIVUS assessment of azygos and IJ veins showed a higher rate of venous abnormalities than venography. IVUS provides a diagnostic advantage over conventional venography in detecting extracranial venous abnormalities indicative of chronic cerebrospinal venous insufficiency.

Effect of Contrast Material on Radiation Dose in an Adult Cardiac Dual-Energy CT Using Retrospective ECG-Gating

The purpose of this study was to determine the effect of contrast material and retrospective ECG-gating on radiation dose in an adult cardiac dual-energy computed tomography (DECT). Sixty-two patients underwent CT cardiac examination with a Somatom Definition Flash DECT using tube voltages of 100 kV without filter and 140 kV with a tin filter (mean effective mA s: arterial 72.39 and 62.94, venous 93.21 and 78.45, and late phase 134.5 and 118.2). The arterial and late phases were examined with retrospective ECG-gating, but gating was not used for the venous phase. Seventy milliliters (70 ml) iodinated contrast material (CM) was injected into the patient during examination. The effective doses (ED) were calculated from dose-length-product (DLP) and computed tomographic dose index volume (CTDIvol) using the latest k-factor (0.028). Pearson's correlation coefficient was used for statistical tests on continuous variables. Mean CTDIvol and DLP were lower in the late phase (10.15 ± 1.5 mGy and 202.9 ± 23 mGy cm) compared to the arterial phase (19.69 ± 3 mGy and 394 ± 90 mGy cm). Differences between the arterial and late phase were statistically significant (p = 0.005), and mean values for the late phase were 48.5% lower than mean values for the arterial phase. Mean CTDIvol and DLP were lower in venous (7.72 ± 1 mGy and 154.3 ± 17 mGy cm) compared to late phase (10.15 ± 1.5 mGy and 202.9 ± 23 mGy cm). The difference between venous and late phase was statistically significant (p < 0.001). The mean results for the venous phase were 24% lower than those for the late phase. This study shows that contrast material (CM) absorbs radiation significantly and increases dose by 48.5% in an adult cardiac dual-energy CT with retrospective ECG-gating. Care must be taken to determine the type, concentration, and volume of CM used for the scan. The dual-energy non-ECG-gated technique decreased radiation dose by 24% compared to the ECG-gated technique. ECG-gated cardiac examination should be limited to patients with strong clinical indications. SNR and HU increased with decreasing energy. The image noise values showed a negligible difference in the arterial and late phase datasets, and this did not affect the diagnostic quality of the image evaluation.

Contrast-Induced Acute Kidney Injury

The development of acute kidney injury is not an uncommon complication of invasive cardiovascular procedures requiring administration of radiocontrast, and it is associated with high acute and long-term morbidity and mortality.1–3 Recognized mechanism of acute kidney injury include embolization of atheroma (cholesterol embolism), which has been shown to occur in up to 1.4% of cases in clinical studies4 and in as high as 30% of cases in pathological series,5 and a direct toxic effect of contrast media on renal tubular cells (contrast-induced acute kidney injury). In the absence of cutaneous findings associated with cholesterol embolism, and in the absence of other symptoms and signs of distal embolization, it is difficult to determine the relative contribution of cholesterol embolism to the development of acute kidney injury when compared with contrast-induced acute kidney injury. The pathophysiology of contrast-induced acute kidney injury is complex and includes a direct toxic effect on tubular cells as well as the production of reactive oxygen species.6,7 Reactive oxygen species, by acting as scavengers of NO, lead to a reduction in Po2 and to increased vascular reactivity to various vasoconstrictors including angiotensin II, thromboxane, endothelin, adenosine, and norepinephrine. During the past 2 decades, we have made substantial progress in the identification of risk factors for the development of contrast-induced acute kidney injury2,8 and in the identification of interventions that can lead to a reduction of its incidence. As of today, minimization of the total amount of contrast by modification of procedure strategies and appropriate preprocedure hydration are mainstays in the prevention of contrast-induced acute kidney injury.9–11 In addition, the use of low-osmolar and iso-osmolar contrast media has been found to be beneficial when compared with high-osmolar contrast media.12 However, substantial differences …

Does Nebivolol Prevent Contrast‐Induced Nephropathy in Humans?

An experimental study showed that nebivolol is an effective agent in contrast-induced nephropathy (CIN) prophylaxis. We hypothesized that prophylactic nebivolol use had protective effects on renal function in human beings subjected to iodinated contrast agent since it has vasodilatory effect and antioxidant properties. The present study enrolled 120 patients scheduled for coronary angiography and ventriculography. All patients were hydrated with intravenous isotonic saline. The patients in group I received 600 mg N-acetylcysteine every 12 hours for 4 days. The patients in group II received 5 mg nebivolol every 24 hours for 4 days. The patients in group III were only hydrated. The primary endpoint was the occurrence of CIN. The secondary endpoint was the change in serum creatinine (Cr) levels at 2 days and 5 days after the contrast exposure. Nine (22.5%) patients in group I developed CIN, as did 8 patients (20.0%) in group II and 11 patients (27.5%) in group III (P = 0.72). Changes in mean Cr level from baseline to day 2 were not statistically significant in all groups. However, we detected a statistically significant increase in mean Cr levels at day 5 compared with baseline levels in group I and group III (from 1.42 ± 0.13 to 1.52 ± 0.26, p2 = 0.02; and from 1.43 ± 0.14 to 1.55 ± 0.30, p2 = 0.01, respectively). Although an increase was detected in mean Cr level from baseline to the 5-day Cr level in group II, this did not reach statistical significance (from 1.40 ± 0.12 to 1.48 ± 0.23, P = 0.06). Pretreatment with nebivolol is protective against nephrotoxic effects of contrast media.

Minimizing contrast medium dose during transapical aortic valve implantation: it is worth the effort

Madershahian et al. [1] have examined a clinically important issue—the influence of contrast media dose on adverse outcomes post-transapical aortic valve implantation (TA-AVI). The authors retrospectively examined 50 TA-AVI patients with an elevated preoperative creatinine (>1.3 mg/dl) and determined that an elevated dose of contrast media (> 100 ml) was associated with higher mortality, as well as a trend towards increased intensive care unit (ICU) length of stay. Although the investigators failed to find that elevated contrast media dose was an independent predictor of mortality, this may have been due to the relatively small sample size of the study. The described association between contrast media dose and adverse outcomes post-TA-AVI is an important finding, but not particularly surprising. Pre-existing renal impairment is a fairly common finding in TA-AVI patients. Such patients have a high incidence of congestive heart failure, peripheral vascular disease, diabetes and hypertension—all known risk factors for renal impairment. Contrast-induced nephropathy may frequently occur in such patients, particularly if they have recently undergone cardiac catheterization or computed tomography. It is for these reasons that we try to maximize the period of time between transcutaneous aortic valve procedures and preoperative contrast-based investigations in patients with pre-existing renal impairment. Acute renal failure post-TA-AVI is a fairly common complication. A previous study from our centre revealed a 16% prevalence of acute kidney injury (AKI), defined as a decrease in estimated glomerular filtration rate of> 50%, in 270 TA-AVI patients [2]. Patients with AKI had increased ICU and hospital lengths of stay. In addition, AKI was an independent risk factor for in-hospital mortality (odds ratio 5.9), and 1-year survival was markedly decreased in AKI patients (45 vs. 80% in patients without AKI, P < 0.001). The administration of more than 90 ml of contrast dye during the TA-AVI procedure was an independent predictor of postoperative AKI. We concluded that contrast media dose should be minimized during TA-AVI in order to decrease the risk of postoperative renal failure. Acute renal failure can occasionally lead to multiple complications, such as respiratory insufficiency, intubation, prolonged intensive care stay and even mortality in TA-AVI patients, probably because of their pre-existing comorbidities and reduced physiological reserve. Acute renal insufficiency post-cardiac surgery most frequently arises on postoperative days 1–3, and may occur without any recognizable preceding factors [3]. The occurrence of AKI with the abovementioned cascade of complications can be particularly vexing in patients with a heretofore completely uncomplicated TA-AVI procedure. The main drawback of the study from Madershahian et al. [1] is the inability to determine if the relation between increased contrast media and worse post-TAVI outcomes is associative or causative. That is, was the increased contrast media dose a consequence of a complicated TAVI procedure that subsequently lead to worse outcomes, or did the contrast media in and of itself lead to renal failure and subsequent morbidity and mortality? The longer operative time in the high contrast media dose group would suggest that these patients experienced a more complicated intraoperative course, although this may also be explained by their operations being performed in the earlier part of the operators’ learning curve. Unfortunately, the authors were unable to assess for other possible markers of procedure complexity including valve deployment difficulties, coronary obstruction, catecholamine requirement or low cardiac output syndrome. In addition, patients who received a higher contrast media dose had a higher risk preoperative profile, including prevalence of coronary disease and EuroSCORE predicted risk of mortality, further complicating interpretation of the results. However, the authors’ conclusion that excessive contrast media usage should be avoided in patients with pre-existing renal impairment seems prudent and logical. Some investigators have reported that TA-AVI procedures can be performed with the administration of minimal or no contrast media [4]. The potential beneficial effects of contrast media avoidance, however, need to be weighed against the risk of possible difficulties in precise valve positioning during deployment. Although complete elimination of contrast media may not be feasible in the majority of the TA-AVI patients, contrast dose minimization is a reasonable and worthy goal. In addition, awareness of the nephrotoxic effects of contrast media within the cardiac surgery community needs to be

Néphropathie induite par les produits de contraste iodés en réanimation

A growing number of imaging procedures requiring intravenous administration of iodinated contrast media are performed in the intensive care unit (ICU). Renal toxicity of contrast media added to the multiple renal injuries suffered by the critically ill patients may influence the outcome. The incidence of contrast-induced nephropathy (CIN) in the ICU is difficult to determine because of so many definitions used. Applying the definition of the Acute Kidney Injury Network, about 10–20% of ICU patients receiving iodinated contrast media will develop CIN. In addition to patient’s severity assessed by the Sequential Organ Failure Assessment score, few other ICU-specific risk factors have been identified. The independent effect of contrast media on the kidney function of patients with multiple factors of renal injury is difficult to evaluate and, in the context of emergency imaging, the scarce comparative studies of patients who are either undergoing or not undergoing iodinated contrast-media infusion did not report any difference in the incidence of acute kidney insufficiency. Nevertheless, the independent effect of contrast media, even if minimal, is likely to influence critically ill patients’ outcome, given the poor prognosis of acute kidney insufficiency in this population. Thus, strategies based on the risk/benefit ratio assessment and including hypovolemia correction and preventive drug administration are considered in the light of recent international guidelines.

Carotid CT-angiography: Low versus standard volume contrast media and low kV protocol for 128-slice MDCT

Availability and utilization of computed tomography angiography has been increasing recently. We aimed to assess the effectiveness of low amount of contrast media and low kV value in order to reduce possible side effects of contrast media and to provide optimization of kV value in the evaluation of the carotid artery with multi-detector computed tomography angiography. Forty one patients were randomized into two groups. Contrast media was administered at a dose of 1ml/kg in group A patients and of 0.5ml/kg in group B patients. kV value of 120 in group A and 100 in group B were chosen. Bolus tracking technique was used. Attenuation values of certain arterial segments were measured, and values over 200HU were considered as significant. North American Symptomatic Carotid Endartherectomy Trial criteria were utilized in the evaluation of stenosis. Image quality in arterial segments of all cases was found to be sufficient for diagnosis. Arterial attenuation values were found to be higher in group B than group A. When compared separately in all arterial segments, there was no statistically significant difference between the groups. For stenosis, 615 arterial segments were evaluated. Moderate stenosis in eight segments and severe stenosis in three segments were identified in group A. Occlusion in three segments, severe stenosis in three segments, and moderate stenosis in 25 segments were detected in group B. Better image quality can be obtained, and the amount of contrast media can be reduced using low kV technique in carotid artery multi-detector computed tomography angiography examination.

Effect of contrast material on image noise and radiation dose in adult chest computed tomography using automatic exposure control: A comparative study between 16-, 64- and 128-slice CT

Purpose To determine the difference in radiation dose between non-enhanced (NECT) and contrast-enhanced (CECT) chest CT examinations contributed by contrast material with different scanner generations with automatic exposure control (AEC). Methods & materials Each 42 adult patients received a NECT and CECT of the chest in one session on a 16-, 64- or 128-slice CT scanner with the same scan protocol settings. However, AEC technology (Care Dose 4D, Siemens) underwent upgrades in each of the three scanner generations. DLP, CTDIvol and image noise were compared. Results Although absolute differences in image noise were very small and ranged between 10 and 13 HU for NECT and CECT in median, the differences in image noise and dose (DLP: 16-slice:+2.8%; 64-slice:+3.9%; 128-slice:+5.6%) between NECT and CECT were statistically significant in all groups. Image noise and dose parameters were significantly lower in the most recent 128-slice CT generation for both NECT and CECT (DLP: 16-slice:+35.5–39.2%; 64-slice:+6.8–8.5%). Conclusion The presence of contrast material lead to an increase in dose for chest examinations in three CT generations with AEC. Although image noise values were significantly higher for CECT, the absolute differences were in a range of 3 HU. This can be regarded as negligible, thus indicating that AEC is able to fulfill its purpose of maintaining image quality. However, technological developments lead to a significant reduction of dose and image noise with the latest CT generation.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging for prostate lesions and normal tissue at 3.0-Tesla magnetic resonance imaging

Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined. To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI). Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm(2) before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test. No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm(2)/s Vs 0.89 ± 0.12 mm(2)/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm(2)/s vs. 1.2 ± 0.29 mm(2)/s, p < 0.0001). No significant differences were detected for normal tissue. The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in interpretation.

Impact of anticoagulation on ionic and nonionic contrast media effect on thrombogenesis and fibrinolysis: The PEPCIT study

The effect of ionic low osmolar contrast media (ICM) and nonionic iso-osmolar CM (NICM) on acute thrombotic complications of percutaneous coronary intervention (PCI) is subject to controversies possibly related to a potential interaction with anticoagulation regimens. We sought to compare physical and morphological properties of fibrin clots made in the presence of ioxaglate (ICM), iodixanol (NICM) versus control and to evaluate the effect of four anticoagulants used in PCI. Maximum platelet aggregation (MPA%), maximum elastic modulus (EM, dyne/cm(2) ) fiber density (n/10(-5) /μm(2) ), and lysis front velocity (nm/sec) of fibrin rich clot (FRC) were measured simultaneously using peripheral blood from 12 patients undergoing elective PCI. We compared the effects of adding iodixanol or ioxaglate or saline (control) to blood with enoxaparin, unfractionated heparin, fondaparinux, and bivalirudin. Iodixanol and ioxaglate led to nonsignificant reduction in MPA compared to control (33.6% ± 16.9%, 28.2% ± 18.9%, and 40.7% ± 13.9%, respectively, P = ns). Fibrin formed with iodixanol was stiffer (42.7 ± 41.9, 18.7 ± 3.7, and 15.9 ± 9 dyne/cm(2) , P < 0.01) and displayed more fibrin fibers (1089 ± 175, 260 ± 108, and 456 ± 131 n/10(-5) /μm(2) , respectively, P < 0.01) than with ioxaglate or control. This resulted in a profound reduction in the lysis front velocity (191 ± 95, 261 ± 112, and 360 ± 153 nm/sec). None of the four anticoagulants displayed any significant interaction on the effect of contrast media. The prothrombogenic effect of iodixanol is related primarily to an increase in fibrin stiffness with subsequent delayed fibrinolysis, something not seen with ioxaglate. Anticoagulation does not appear to have any impact on this fibrin clot abnormalities.

The effect of contrast media on nucleus pulposus cell viability in vitro

The effect of contrast media on nucleus pulposus cell viability in vitro